This is a known issue that I have encountered before and it's already logged as an SPR

"SPR 770865 - 'Extra edges are seen near the holes for this assembly in SVG created from Technical Illustration workshop'."

There's a couple of things that you can do to reduce/eliminate these aretfacts. The first thing is to change the Geometry Compression setting to Low (see below). In the instance that I encountered this behaviour this setting eliminated all but one of the lines and Adobe Illustrator was used to erase it. Another workaround is to convert the body to a .stp file and import into Composer. Can't really explain why that one seems to work but it does!